Script - How to add UV map for each object in scene?
Add UV to all mesh objects in scene

Note: for 2.8x replace uv_textures with uv_layers and add (name="yourUVname") in .new()

import bpy
context = bpy.context
scene = context.scene
# all meshes on mesh objects in scene
meshes = [o.data for o in scene.objects
        if o.type == 'MESH']
# add a new "map1" UV to each        
for m in meshes:
    m.uv_textures.new("map1")


Note could be done in list comprehension with

uvs = [o.data.uv_textures.new("map1") for o in scene.objects
        if o.type == 'MESH']